Existing methods for detection of radioactive materials have very limited range (less than a few meters). In addition existing methods are passive resulting in limited sensitivity. The Geiger-Muller tube is the most common type of radioactivity detector. A recently proposed active radioactivity detection concept is based on a high power THz pulse inducing avalanche breakdown and spark formation in the vicinity of the radioactive material, but has very limited stand-off detection range.
It would therefore be desirable to remotely detect radioactive materials with greater precision and specificity.